Equal Amount of Vertices?
Morphing smoothly between two totally different objects with different vertex counts that also contain submeshes like text or single words is done more easily and efficiently by using particle systems and keyed physics. You basically "fill" your objects (the meshes with its submeshes which in this case are our letters) with particles and then use keyed physics to do the transition. 

I recommend the video tutorial from BlenderHQ which you can find here:

Morphing Particle Systems with keyed Physics in Blender